Rotate Models Incrementally
It's a little hard to tell exactly what you're asking, but if you're looking to form a bunch of objects into a 180° semicircle, you can use an Array Modifier:



Just use an Empty as the offset object of the modifier, and keep the origin of the object in the same place as the empty. Then you can rotate the empty by 180/(35-1) to get the right increments to fill up 180°.